Regarding the American Continent, four (4) capitals are analyzed in this research. These capitals during typical periods, BQut, present a moderate AQI level, where Bogota is the capital with the highest PM2.5 concentration with an average of 98 μg/m3. Followed by, Mexico City with 74 μg/m3, Santiago de Chile with 68 μg/m3. Finally, Lima registers an average concentration of 58 μg/m3. As well as, the period in confinement in Bogota, presents the greatest decrease in the cities analyzed during the Qut, with a 57% PM2.5 reduction. Santiago de Chile, does not present quarantine in the entire city but in seven specific communes, which registers a 10% reduction in the concentration of this particulate matter. Mexico City presents a voluntary quarantine by the population without government restrictions, however a 2% reduction is observed during the study week in Qut. (Fig. 5 ).
Fig. 5 Capital cities Bogotá, Lima, Mexico City, Santiago de Chile and Kampala (Africa) PM2.5 levels before and during quarantine (WAQ Index, 2020).